Wednesday 14 September 2011

Ducati 250 Mark 3

What kind of profound stupidity causes an engine designer to place the kickstart on the left side of the bike? Especially a bike like a Ducati 250 Mk 3, which has such strong compression in its single cylinder layout that I find I could actually stand on the kickstart all day long if I had a mind to do something so wasting of my time and generally foolish. I could, I suppose, spend the rest of this article complaining about just how bloody difficult it is starting the little blue Ducati, but you have heard it all before; it is after all part of the Ducati single myth.

I put up with this ankle shattering deficiency because I fell in love with the bike on first sight and have not yet, two years later, recovered from the shock to my system. I love the lines of this machine, such simplicity yet the whole motorcycle experience is brilliantly rendered. The 1974 machine was absolutely immaculate throughout, had done only 19000 miles and was worth two thousand notes of anybody's money. Since purchase I have done 7000 miles, mostly when the sun was shining and mostly down winding country roads where the machine can really show its abilities.

However, part of the price of buying a long stored, low mileage machine was that the electrics were the original 6V dross; or what was left of them. The insulation on the wiring was quietly rotting away, causing blown fuses and sudden conflagrations. The lights dissuaded one from riding at night and the horn would have been laughed out of court if it were fitted to a kid's bicycle let alone a machine capable of 90mph.

The electrical system although basic was by no means simple, with a rash of spuriously coloured wiring running all over the frame. Once the wires were replaced, a 6 volt Cibie unit added to the front, Japanese switches to the handlebars and a proper means of controlling the voltage and rectification fitted, electrical problems were confined to fitting a spark plug every 2000 miles (starting became impossible if neglected) and 500 mile resetting of the points (the kickback on starting became horrendous if not done religiously). The carb was also a constant source of nastiness, with petrol pouring out and the odd jet doing a runner.

Once started and warmed up (about five to ten minutes) these minor problems faded into the background. The Mk 3 has a thankfully more upright riding position than the back ruining Desmo version. The relative position of bars and pegs suited me just fine, having managed all of 175 miles in an afternoon without incurring my wrath. Once in motion, wrath was usually the last thing in my mind, for I find the little Ducati a thoroughly enthralling motorcycle to ride, like none I have tried before or since.

I have ridden both Japanese and British 250 singles - there really is no comparison. The Ducati's sophisticated mechanicals and high quality of construction, being more hand built than most, shine through. Where a BSA B25 is horribly rough at most revs the Ducati impresses with its smoothness. Where a Honda RS250 irritates with its constant need for revs, the Ducati surprises with its excessive low speed torque and willingness to rev to the red sector. These engines have developed according to the old school of motorcycle design, first seeing the light of day in smaller form in the late fifties and gradually evolving into their seventies shape until their very sophistication became their undoing when they could no longer be economically produced due to the high content of expensive, experienced labour involved in their construction. Which was lucky enough, in its way, as it assured that secondhand values have remained high.

The Mk.3 puts out around 28 horses, enough for an easy 90mph. Those totally neglectful of the mechanical integrity of their motorcycles will doubtless extract even more. A few relatively simple tuning mods, involving use of a Amal carb, an even louder exhaust and a bit of port smoothing can push the little beast beyond the ton, but I find performance quite adequate to my needs in stock set- up.

The Desmo version is basically identical with the addition of an extra set of camshaft lobes and rockers to close the valves by mechanical means rather than relying on valve springs (although a very light set of springs are used to hold the valves closed when the engine is cold). The advantages of such a set-up only really evident in racing conditions when the engine is flogged for hour after hour at high revs. The 250 Desmo is slightly faster than the Mk.3 but I reckon this is down to its head in the clocks riding position rather than anything else.

The engine range is almost unique in its refusal to employ chains internally, the camshaft driven by bevel gears which are difficult and therefore expensive to set up and primary drive is by gears - nothing new to the Japanese, of course, but the engineering finesse would have caused an uproar in the boardrooms of a British motorcycle company in the sixties were it suggested for a BSA 250 and the like. Admittedly, the side is rather let down by the only chain on the bike, for the final drive, which true to the nature of single cylinder engine pulses destroys itself in less than 5000 miles and requires almost constant care and attention.

The speedo is naturally another piece of poor engineering, the needle flickers randomly around the dial and when it is steady can be as much as 15mph out. The rev counter is rather more reliable, but cables only last for about 1500 miles. After a while, you learn to listen to the beat of the exhaust and the rush of the air when an accurate idea of speed is required.

That and the force with which bumps are fed through to the rider. Don't get me wrong, the Ducati is a fine handling a machine as you'd find built in the seventies but it derives its handling finesse from a rigid frame (with engine as a stressed member), steering geometry that is very conservative (although the machine is still flickable because of its low mass) and suspension that hardly gives an inch on most road surfaces. The bike and rider are bounced around a lot but the chassis cleaves through the jostling on its chosen path, come what may.

The light mass also helps the effectiveness of its power delivery. The Ducati is so light that you might expect it to wander all over the road, but its tenacity is such that you can almost think your way around corners, the bike appears to have placed itself on the required course almost before you've thought about it. This uncanny ability combined with a punchy power delivery (aided and abetted by a most surprisingly smooth gearbox that would shame many a modern Honda), makes very short work of even the most tortuous of back roads and leads to a massive grin in short order.

The Duke will also, when necessary, cruise down motorways at around 80mph for as long as you can take the wind blast, although such abuse is to lose the point of the machine. Town riding is ruined by a clutch that drags as soon as the engine starts to overheat, although the extreme narrowness of the machine does aid a fast pace through heavy traffic. The steering lock limits rapid U-turns. The heavenly growl made when rumbling through towns in the lower gears is certainly a useful safety factor as it makes car drivers think they are about to be mown down by an out of control tractor.

The Mk.3 sports a useful set of drum brakes, which are powerful enough for emergency stops in town and have not needed any attention. They do fade from repeated high speed stops.....on a couple of occasions I've had my heart in my mouth as I've found the front brake fading away to nothing, entering a corner 20mph too fast, only the excellence of the Duke's chassis letting me get out of the situation alive.

When I fist bought the bike I was amazed at how far it would travel on a gallon of petrol - 85 to 95 miles, although I have done as much as 100mpg. All the more amazing when you consider the machine sports a horrible Italian carb that was reviled from new and is well worn in now! It's just as well it's good on fuel because it needs its engine oil changed every 500 miles.....neglect leads to extremely rapid engine wear. Ultimately, the big-end and crank give out, which is an extremely expensive business to sort.

I can see that the machine will not be to everyone's taste, but to me it's a pure bit of the motorcycle experience, the distillation of one man's engineering genius and a lovely hustle on the back roads. Being a member of the Ducati's Owners Club, unfortunately, meant I was able to have a short ride on one of the old 750SS vee twins. I was left gasping for breath at the sheer brilliance of this machine and have vowed I must add one to my stable at all costs, even if they are absurdly priced.

Dave

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There are lots of myths surrounding Ducati singles. The biggest must be how hard they are to start. As a lad I learnt how to kick into life big British thumpers - Panthers, BSA B33's, etc. The Ducati was pretty easy after that apprenticeship. Someone had already fitted an Amal carb and degutted the silencer. Stock bikes with the Del'Orto carb are probably a different story. The 250 runs a very high compression ratio so you can stand on the kickstart! Quite off-putting to wimps and thieves. The one thing that can throw the starting is slipped ignition timing - check it every 500 miles!

The valves need to be checked and adjusted every 1000 miles. The MK.3 differs significantly, from the 250 Desmo, in the design of its cylinder head, has valves that are easy to adjust but need more frequent attention than the desmo design. The latter has the valves both opened and closed by cams, a lightweight spring used to hold the valve close when the motor's cold and all the clearances haven't been taken up by the heat generated by a running engine.

And they do run very hot. Oil's best changed every 500 miles! There's a lot of incredibly fine engineering inside the cases that needs plenty of clean, good quality oil - bevel drive shaft for the camshaft, gear primary drive, piston/bore clearances that are very small, etc.

Ducati produced this engineering masterpiece and mounted it solidly in a really minimal tubular frame - the single tube running down from the headstock to the engine doesn't even run under the motor, the latter a stressed member. This is where good engineering comes into play. By making the whole bike so light and narrow, the stresses throughout the chassis were minimised. This is the bike's essence and what makes it such a delight on the open road.

It goes where it's pointed with an uncanny accuracy and with just the lightest of touches. The front end's off a late Desmo, with single disc, that doubtless aids accuracy. The disc needs a heavy hand but doesn't suffer lag in the wet and can howl the tyre when necessary. I don't like brakes that lock up under one finger pressure, so this set-up's fine by me.

The biggest problem with any single's the vibration they put out. The 250 isn't in the same dire bracket as the 450 version, but it does thrum away as the revs rise and can fall over if left on the stand at tickover. Now, I've ridden some modern bikes, like the CB250RS, that have balancers - and I hated them. Give me the rawness and brutality of the Duke any time. Just be aware, that if you've never ridden one before, that these high priced classics (don't blame me, it makes me sick as well, because I'd like to buy a 350 or 450) will come as a bit of a shock on the first ride! You do get used to them quickly, though, and soon fall in love.

That vibration is responsible for the terrible reputation of the 6V electrics. This is the era of Ducatis when the ancillaries were tacked on as an afterthought, without any regard to British winters. Basically, all the electrical components fall apart and the wiring rots as fast you can tape it. It's inconceivable that any machine has survived this long without having the electrics replaced, so like the starting it shouldn't be a major problem.

Even with a 12V conversion, the generator's not up to powering a decent front light. Even if it was the vibes would still get to the bulb! Even when roaring down my favourite country lanes, which I knew really well, that lack of illumination proved hallucinatory. I'd swing left when the road was going right, sending the chassis into a real tizzy but somehow hanging on until we hit a ditch or some other obstacle. Painful!

Lack of comfort was also evident in the ride quality. The price paid for the supreme accuracy of the steering was suspension so stiff that it often seemed rock solid. Bumps were fed straight into arms and backside (the seat not being that well padded and with a tendency to fall apart every six months), leaving me bruised and sore for the first couple of months until my body adapted to it.

What with the vibes singing through the chassis, I often wondered why I was going out of my way to subject myself to such torture. However, a twist of the throttle, a hustle through the gearbox and a series of tight bends, reassured me that I wasn't going completely mad. The 250 can take on most 250 to 400 twins of the seventies and eighties but has a hell of a job staying with a derestricted TZR 125. I found this out the hard way. They both share 90 to 95mph top speeds and searing acceleration when the throttle's used in anger, but the TZR's sophisticated suspension means it just flows over bumps and holes rather than trying to throw the rider off. The Duke somehow maintained its line but I couldn't use the extremes of the performance - the Yamaha rider could and I was left way behind.

We swapped bikes for a short time. I don't even like strokers but was quickly enamoured. The wailing spannie was a bit off-putting after the grunting Ducati but the way the power suddenly poured in, as if someone had flicked a switch (the powervalve working), nearly gave me a heart attack. The front wheel reared up and I grinned like a 16 year old after his first bop. Ride and handling were a revelation. I think I just made myself a prime target for the old farts at the Ducati's Owners Club.

Some more praise for the Mk.3 (quick). There's no way that the TZR or any 250 can match the Ducati's economy. So fine is the blend of stroke, bore, valve and ignition timing, so exquisite and accurate the engineering, that the bike gives 70 to 100mpg! As someone who grew up with British thumpers I can't express too much astonishment that a modern design of a single's both frugal and powerful, it just makes you wonder what the hell the Japanese have been doing all this time. The TZR owner reckoned on 50 to 60mpg, but that's not really a fair comparison. Many modern Japanese bikes, like the newest CB250 twin, have mediocre performance and poor economy. I don't know what's Ducati's secret but it's amazing that the Japanese haven't reverse engineered it.

The one area of the Mk.3 that's expensive is the drive chain and sprockets. All that torque and the destructive single cylinder pulses are concentrated in the final drive. About 4500 miles for the chain, and not much more for (pattern) sprockets - maybe the originals lasted longer but by the time I bought the bike at 15000 miles they were long gone.

The clock now reads 22000 miles but that's meaningless as the mileometer is crap, affected by the vibes. Closer to 40,000 miles after ten years of summer use (I have an XBR500 for winter, but that's another story - boring, but safe and reliable). Only ride one of these Dukes through winter if you want all the paint and chrome to fall off. The engine was so expensive to build that they had sod all left to pay for a decent finish - it's worse than that because some of the metal seems to seep out rust even when resprayed!

The engine has so far been reliable - meticulous maintenance and frequent oil changes. They can blow the small or big ends if run on old oil and the gearbox selectors do wear. Back in the seventies there were quite a few rats around, but those have all disappeared. Either rebuilt or dismembered for spares. Beware of some bikes purporting to being Desmo's when they are Mk.3's with cafe racer clothing. Prices can be as high as three grand, which is plainly ridiculous (yes, you can have mine for that). £1500 for a good one is more than enough. They are fun but there's also lots of pain!

H.T.